Peliosanthes annamensis N.Tanaka, Aver., V.C.Nguyen & K.S.Nguyen, 2023

Averyanov, Leonid V., Nguyen, Van Canh, Tanaka, Noriyuki, Nguyen, Khang Sinh & Maisak, Tatiana V., 2023, Three new taxa and two noteworthy species of Peliosanthes (Asparagaceae, Convallarioideae) from Laos and Vietnam, Phytotaxa 609 (3), pp. 209-221 : 210-212

Peliosanthes annamensis N.Tanaka, Aver., V.C.Nguyen & K.S.Nguyen , sp. nov. ( Fig. 1 )

Diagnosis: —Most similar to P. crassicoronata , but differs mainly by its smaller leaves (blades 18–32 vs. 33–41 cm long) with fewer longitudinal veins (14–21 vs. 35–49) per blade, shorter peduncle (1.5–3.5 vs. 3.5–7.5 cm), bracts nearly as long as (vs. shorter than) open flowers, broadly obconic (vs. broadly crateriform) perianth tube, ovate or triangular ovate (vs. broadly ovate to subcircular) perianth segments, less convex purple-speckled dull (grayish) white (vs. purple-violet) staminal corona, and half-inferior (vs. superior) ovary.

Type: — VIETNAM. Dak Lak Province: M’Drak District, Chu Mu Mountain, evergreen forest at elevation about 500 m a.s.l., 10 February 2023, V. C. Nguyen s.n., type herbarium specimen prepared from cultivated plant, 18 February 2023, V. C. Nguyen, L. Averyanov, AL 2038 . Holotype LE: LE01170310 (https://en.herbariumle.ru/?t=occ&id=166012). Photos of the cultivated plant used for preparing the type specimen – LE: LE01123813 (https://en.herbariumle.ru/?t=occ&id=165102).

Etymology: —The specific epithet refers to the former name of central Vietnam ( Annam), from which the new species was discovered.

Description:—Herb terrestrial, rhizomatous, acaulescent, evergreen perennial. Rhizome plagiotropic, horizontal to ascending, simple or few branching, 1–2(2.5) cm long, (4.5)5–6(7) mm in diameter, covered with few remnants of papyraceous whitish bracts, producing many rigid fleshy brownish roots. Stem ascending or erect, 1.5–2 cm high, covered with few remnants of herbaceous lanceolate pale brownish bracts to 5 cm long. Leaves much exceeding flowering stem; petiole erect, straight or slightly arcuate, (12)15–30(35) cm long, rigid, stout; leaf blade narrowly elliptic to elliptic, (18)20–30(32) cm long, (4)5–7(8) cm wide, leathery, glabrous, glossy, grass green above, light green below, acute to shortly acuminate, with many longitudinal veins (14–21 veins including marginal ones in middle part); secondary transverse veinlets numerous, distinct, oblique to perpendicular to longitudinal veins. Flowering stem (peduncle and inflorescence) (12)14–16(18) cm long; peduncle erect, (1.5)2–3(3.5) cm long, 2–2.5 mm in diameter, dull olive green to dull violet, stout; sterile bracts on peduncle 2–3(4), narrowly triangular ovate, 1.5–2.5 cm long, (4)5–6(7) mm wide at base, acute or acuminate, papyraceous, dark purple; inflorescence a raceme, rachis (10)12–14(16) cm long. Floral bracts 2 (outer bract 1 and inner bracteole 1) at base of pedicel, narrowly triangular to lanceolate, with tapering to acute apex, light green to pale violet, herbaceous; bract (4)5–10(12) mm long, (1.6)1.8– 3(3.2) mm wide, descending to horizontal, nearly as long as open flower; bracteole borne often at right angle to bract, shorter than half of bract. Flowers sparser toward apex of rachis, blooming acropetally, solitary in axils of bracts, cernuous, campanulate, not widely opening, (5)5.5–6(6.5) mm high, (6.5)7–7.5(8) mm wide. Pedicel cylindric, curved downward, purplish, 2.4–3 mm long. Perianth distally 6-cleft, fleshy, abaxially dark purple-violet or brownish purple, glossy, adaxially dark purple-violet; tube broadly obconic (or funnelform), 1.2–1.6 mm high, (5.6)6–6.8(7.2) mm in diameter at apex; segments 6 in 2 whorls of 3, triangular ovate or ovate, (3.8)4–5(5.2) mm long, (3.4)3.6–3.8(4) mm wide, adaxial basal portion whitish, subacute or obtuse at apex, only slightly imbricate proximally. Corona slightly convex, dull (grayish) white, speckled with violet especially around apical orifice, 0.5–1 mm high, (4.8)5–5.5(5.2) mm in diameter, orbicular at base; apical opening almost circular, entire, 1.4–1.6 mm in diameter. Anthers 6, sessile, introrse, ovoid, 0.4–0.5 mm long, about 0.4 mm wide, pale beige; pollen cream-white. Pistil half-inferior (in ovary part), distal free part conoid, 1.8–2 mm high, 2.8–3 mm across at base, hexagonal at base, white speckled with purple, distal portion including stigma dark purple; ovary internally incompletely 3-septate, each locule containing 3–5 ovules on basal central placentae; stigma 3-dissected, lobes narrowly obovate, 0.2–0.3 mm long, radially spreading, finely papillose, dark purple. Fruits unknown.

Ecology and phenology: —Occurs in primary or old secondary lowland evergreen broad-leaved forests on granite at the elevation of about 500 m a.s.l. Flowering in January–March.

Conservation status: — Only a few mature individuals were found in the type locality. With no detailed information on the occurrence, the conservation status of the new species is estimated as “Data Deficient” ( DD), following the guidelines in IUCN (2022) .

Distribution: — Vietnam, Dak Lak Province (M’Drak District). Known only from a single location in the Chu Mu Mountains.

Taxonomic relationships: —In sharing comparatively large leaves (up to ca. 70 vs. 97 cm long), a short peduncle relative to the inflorescence rachis, drooping purple-violet flowers, which become sparser toward the apex of the rachis, and a conoid pistil, Peliosanthes annamensis appears closest to P. crassicoronata K.S.Nguyen, Aver. & N.Tanaka in Nguyen et al. (2020: 41). It is, however, clearly distinguishable mainly by its shorter petiole (12–36 vs. 47–56 cm), smaller leaf blades (18–32 × 4–8 vs. 33–41 × 7.5–10.5 cm) with fewer longitudinal veins (14–21 vs. 35–49), shorter peduncle (1.5–3.5 vs. 3.5–7.5 cm), bracts nearly as long as (vs. shorter than) open flowers, broadly obconic (vs. broadly crateriform) perianth tube, ovate or triangular ovate (vs. broadly ovate to nearly circular) perianth segments, slightly convex (vs. broadly hemispheric) purple-speckled dull (grayish) white (vs. purple-violet) staminal corona, half-inferior (vs. superior) pistil, and smaller anthers (0.4–0.5 vs. 0.9–1 mm long) with pale creamy white (vs. yellow) pollen. Peliosanthes annamensis occurs in Dak Lak Province, while P. crassicoronata is distributed in Gia Lai Province. The former is more southerly distributed, and about 200 km distant from the latter.

Figures

FIGURE 1. Peliosanthes annamensis. A. Leaves and inflorescences detached. B. Basal portion of flowering plant. C. Inflorescences. D & E. Portion of inflorescence. F. Flowers, view from above. G. Flower, side view. H. Flower, rear view. I. Flower with corona removed, showing pistil. J. Flower with corona and distal part of pistil removed, showing interior of ovary. K. Corona, external view. L. Corona, view from underside. M & N. Flower, longitudinally sectioned. Photos, photo correction, and plate design by L.Averyanov and T. Maisak, type specimen V.C. Nguyen, L. Averyanov, AL 2038.